Wildone
6mil may not be enough, it isn't just snow you have to worry about. I had many small tears over the winter caused by falling icicles from the mast/rigging, pointy things falling 20-30ft can do a lot of damage, at least the tarps have a weave that helps stop a tear, plastic sheeting will not. Repairs are easy enough with tyvec tape, only thing I found that would adhere to a cold tarp.